This paper aims to study the reliability of vehicle-mounted LCD displays in high-temperature and high-humidity automotive environments. It analyzes the dual value of improving reliability in reducing driving safety hazards and maintenance costs. The paper reveals the current technical bottlenecks faced by vehicle-mounted LCD displays, including the performance decay of and moisture-resistant materials, the shortcomings in the design of sealed and heat dissipation structures, and the lack of conformity between simulated environment tests. Based on this, the paper proposes systematic improvement strategies: adopting new composite materials to upgrade key components such as polarizers, liquid crystal layers, and sealing gels; constructing a "three-layer and three-interface sealing system and a "zoned heat conduction, key insulation" heat dissipation structure; and establishing a "three-dimensional scenario, four-stage evaluation" simulation test system.